The emission of greenhouse gas being discharged in South Korea is world top 10 based on 2005, and the emission increase speed is currently No. 1 in the world together with China. The global regulation according to emissions of greenhouse gas is about to be tightened up in the future by coming into effect of Kyoto Protocol imposing reduction obligations of greenhouse gas, so the pan-governmental measures responding this are necessary in our country, South Korea. When we bear reduction obligations by about 10%, several tens of millions tons of greenhouse gas emissions should be reduced every year, and this means that domestic companies should bear expenses of several trillion won every year.
The mineral carbonization is a method that can fix CO2 inside the crystal structure of minerals, and makes it a carbonate mineral form by combining natural minerals or industrial by-products including Ca, Mg, Fe elements with CO2, and it is expressed as the following reaction scheme.MO+CO2=MCO3+heat(M=Ca,Mg,Fe)
The mineral carbonization method has many advantages such as needlessness of additional monitoring, etc. because it doesn't have a problem of a disposal site compared to underground disposal, and its disposal is certain and stable. Especially, when compared to the underground disposal, the mineral carbonization method is very advantageous in a problem on a time that CO2 gas can be disposed actually and stably, but it is known as unfavorable in aspects of treatment volume and treatment expenses. For underground disposal of carbon dioxide, the technology first separating, recovering, liquefying and transporting and burying carbon dioxide underground (oil field, etc.) is known.
On the other hand, gypsum as by-products is generated at fertilizer production plants and coal-fired power plants, and at present, it is being generated by 1.5 million tons every year at coal-fired power plants. Gypsum as by-products is partially reutilized in gypsum boards, etc. Theoretically, gypsum of 1.5 million tons/year can dispose separately recovered carbon dioxide of 0.4 million tons/year. The chemical composition of gypsum is CaSO42H2O as optimal raw materials of mineral carbonization.
The method for fixing carbon dioxide by using waste gypsum is disclosed in KR Patent Application No. 10-2009-0063840. However, the efficiency of the above patent is low because the fixed carbon dioxide is less than supplied carbon dioxide. In addition, since there is an essential process that should previously collect and concentrate CO2 gas being used for fixation reaction, there is a shortcoming that it requires high cost.